A number of patents have described devices such as seats and the like that can be used outdoors and heated so as to provide warmth to a user. See, for instance, U.S. Pat. Nos. 5,121,739 (Barker), 4,913,126 (McCall), 4,860,726 (Barker), 4,676,223 (Peterson), 4,495,935 (Lanier), 4,475,532 (Woods), 3,024,782 (Knopps), 2,904,031 (Scott), 2,845,924 (Benda), 2,829,635 (Teller), 2,517,254 (Steele), 208,251 (Mains), and 54,808 (Wright).
Certain of these devices are intended to serve two or more purposes, for instance, by providing both cooking and seating surfaces, or for heating both tents and individual users. As a result, many of them are not particularly well-suited to the singular purpose of effectively warming a person sitting on the such a device. It likewise appears that very few, if any, of such devices are widely commercially available.
One example of a commercially available seat is a device called a "Heat Seat", that involves the use of jelled heat fuel held within a vent-type insert that is itself held by the cover of a carrying pail.
A number of disadvantages are associated with devices such as those described above. Many of the devices, for instance, involve the transfer of heat to the sitting surface itself, thereby warming the person, at least in part, by providing for direct contact between the user's body and a heated surface. In many of these, and other, devices, the user's own body may also serve to block or obstruct the flow of heated air.
Direct contact between the body and a heated surface requires that the seating surface be sufficiently covered, as by intermediate layers, or that its temperature be kept sufficiently low, so as to avoid discomfort, or even burning of the user. Devices and seating positions that use the body to block the flow of warm air can raise similar concerns.
Many other devices can be cumbersome to carry, or to assemble and/or use, particularly in situations where the user must also carry assorted other gear and where the user may be wearing cumbersome clothing.
What is clearly desired is a simple, portable, and effective heated seat device that overcomes the problems such as those described above.